Establishing a virtual tunnel between two computer programs

ABSTRACT

A system transfers data via a communication session between a client application and a server application, where the client application runs on a first network and the server application runs on a second network. The system includes a proxy having a socket to the client application. The proxy converts data between a local protocol run on the first network to a non-local protocol. An agent creates a socket to the server application. The agent converts data between a local protocol run on the second network and the non-local protocol. A server is in communication with the proxy and the agent. The server contains a message queue dedicated to the communication session. The message queue stores data transmitted during the communication session.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.60/449,213, filed on Feb. 21, 2003, the contents of which areincorporated herein by reference.

BACKGROUND

Many products, both hardware and software, have diagnostic tools orapplications for communicating with them. When such products are locatedat customer sites, there is no way to use these tools except to send aservice technician on-site to diagnose and repair any problems.

Tunneling solutions exist that provide a diagnostic program with accessto a remote application. However, such tunneling solutions require aserver at each site to provide access to applications behind itsfirewall. Since the additional server requires additional administrationand maintenance at each site, it is an additional burden to end-users orcustomers.

Furthermore, and perhaps more significantly, installing a server at eachsite that provides tunnel access to a local network also has securityrisks. For example, such a server is addressable via the Internet, andthus is a target to break into an otherwise secure network.

SUMMARY

In general, in one aspect, the invention is directed to a method oftransferring data via a communication session between a clientapplication and a server application. The method includes assigning anidentifier to the communication session, creating at least one queueassociated with the communication session, and using the identifier tostore data passed between the client application and the serverapplication in the at least one queue. The client application and theserver application run local protocols, and the data is passed betweenthe client application and the server application via an intermediaryprotocol. The intermediary protocol may be different from the localprotocols or it may be the same protocol as the local protocols. Thisaspect may include one or more of the following.

A socket interface may be created to at least one of the clientapplication and the server application. The data may be transmittedthrough the socket interface. The client application and the serverapplication may be on networks that run the local protocols, and themethod may include converting between the local protocols and theintermediary protocol when passing the data.

The local protocol may be TCP/IP or a serial protocol, such as RS232 andRS485. The intermediary protocol may be HTTP. The method may beperformed by a server, and may also include performing load balancing toselect the server from among plural servers. The identifier may beassociated with the at least one queue, and may be invalidated when thecommunication session terminates.

The communication session may be a telnet session or may be effected viaa Web site. A session record may be maintained, which includes anidentity of a user initiating the session along with other information.

The method may be implemented via machine-executable instructions storedon a readable medium/media. The method may be implemented via one ormore processors on one or more machines executing such instructions.

In general, in another aspect, the invention is directed to a system fortransferring data via a communication session between a clientapplication and a server application, where the client application runson a first network and the server application runs on a second network.The system includes a proxy having a socket to the client application.The proxy converts data between a local protocol run on the firstnetwork to a non-local protocol. An agent creates a socket to the serverapplication. The agent converts data between a local protocol run on thesecond network and the non-local protocol. A server is in communicationwith the proxy and the agent. The server contains a message queuededicated to the communication session. The message queue stores datatransmitted during the communication session. This aspect may includeone or more of the following features.

The proxy may poll the server for data for the client application. Whendata is present for the client application, the proxy may retrieve thedata from the message queue and pass the data to the client application.The agent may poll the server for data for the server application. Whendata is present for the client application, the agent may retrieve thedata from the message queue and pass the data to the server application.

Other features and advantages of the invention will become apparent fromthe following description, including the claims and drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the concept of a virtual tunnelbetween two computer programs.

FIG. 2 is a block diagram of a network containing computer programs(client application and server application) that communicate via avirtual tunnel.

FIG. 3 is a flowchart showing a process for creating a virtual tunnel.

DESCRIPTION

The system described herein creates a virtual communication link (calleda “virtual tunnel”) between two computer programs (e.g., client andserver applications) that are not able to address each other directly.This situation may occur when a client application needs to connect to aserver application at a remote site. The server application may be on acomputer on a customer or partner's non-addressable local network (e.g.,behind a firewall). As such, the client application will not be able toaddress the server application directly.

A virtual tunnel may be used to provide the client application access tothe server application. FIG. 1 illustrates the concept of a virtualtunnel 8 between client application 10 and server application 11.Virtual tunnel 8 enables client application 10 and server application 11to communicate as if there were no firewalls between them (which,typically, there are).

FIG. 2 shows a client local network 14. Client local network 14 includesa device 15, such as a computer, that contains a processor 16, a memory17, and a storage medium 19 for storing, among other things, anoperating system (OS) 20, a Web browser 21, software 22 for effectingnetwork communications, and one or more executable applications (e.g.,computer programs). Among these applications is client application 24.Client application 24 is a computer program for communicating with anddiagnosing local or remote hardware and/or software.

A router (or modem) 25 couples client local network 14 to an externalnetwork 26, such as the Internet/World Wide Web (Web). External network26 may run Internet Protocol (IP), HyperText Transfer Protocol (HTTP)and other suitable protocols. Network connections may be via Ethernet,telephone line, wireless, or other transmission media.

A firewall 27 is maintained between client local network 14 and externalnetwork 26. Firewall 27 may be implemented via software run on theclosest “intelligent” device to external network 26, e.g., router 25 ordevice 15. The firewall prevents others from directly addressing deviceson client local network 14 via external network 26. As a result of thefirewall, only users on client local network 14 (or some defined subsetthereof) are permitted to address device 15 directly.

Client local network 14 may run a local protocol, such as TransmissionControl Protocol/Internet Protocol (TCP/IP), which may be the same as,or different than, the protocols that run on external network 26.Examples of other protocols that may be run on client local network 14include, but are not limited to, serial protocols, such as RS232 andRS485, and proprietary protocols.

Client local network 14 also includes proxy 29, which is used to effectcommunication between client application 24 and a remote serverapplication. Proxy 29 may be a computer program executing on device 15or another processing device, such as a router 25, in client localnetwork 14. In addition to the functions described below, proxy 29performs any conversions necessary between the protocols running onexternal network 26 and those running on client local network 14.

FIG. 2 also shows a server local network 30. Server local network 30 isdepicted as being similar to client local network 14 for the sake ofillustration. In reality, however, the two local networks may be verydifferent.

Server local network 30 includes a device 31, such as a server, thatcontains a processor 32, a memory 34, and a storage medium 35 forstoring, among other things, an operating system (OS) 36, software 37for effecting network communications, and one or more executableapplications (e.g., computer programs). Among these applications isserver application 39. Server application 39 is a computer program thatmay, among other things, provide information to users via externalnetwork 26 or via local network 30. Examples of such informationinclude, but are not limited to, Web pages and diagnostics oroperational control information pertaining to the device.

A router (or modem) 40 couples server local network 30 to externalnetwork 26. As above, network connections may be via Ethernet, telephoneline, wireless, or other transmission media. A firewall 41 is alsomaintained between server local network 30 and external network 26.Firewall 41 may be implemented via software run on the closest“intelligent” device to external network 26, e.g., router 40 or device31. The firewall prevents others from directly addressing device 31 viaexternal network 26. As above, only users on server local network 30 (orsome subset thereof) are permitted to address device 31 directly.

Server local network 30 may run a local protocol that may be the sameas, or different than, protocols that run on external network 26 and/orclient local network 14. Examples of such protocols include, but are notlimited to, TCP/IP, serial protocols, such as RS232 and RS485, andproprietary protocols.

Server local network 30 also includes agent 42, which is used to effectcommunication between client application 24 and server application 39.Agent 42 may be a computer program executing on device 31 or anotherprocessing device, such as a router 40, in server local network 30. Inaddition to the functions described below, agent 42 performs anyconversions necessary between the protocols running on external network26 and those running on server local network 30.

Agent 42 has a local configuration of interfaces. Each interface has aname, IP (Internet Protocol) address, or other information relevant tothe local protocol, such as baud rate. Local configuration of theinterfaces allows a local operator to control access to applications onserver local network.

Proxy 29 and agent 42 perform essentially the same functions (describedbelow) which allow client application 24 and server application 39 tocommunicate via a virtual tunnel. Proxy 29 and agent 42 may bepre-programmed into devices on respective local networks 14 and 30.Alternatively, one or both of proxy 29 and agent 42 may be downloaded,e.g., from external network 26. For example, in one embodiment, proxy 29is an applet that is downloaded from a server 44 on external network 26and that is installed on device 15. The applet may be included in a Webpage that is provided by server 44, and that is accessed by a user whenestablishing a virtual tunnel between client application 24 and serverapplication 39. This process is described in more detail below.

External network 26 contains server 44, which is a computer or any otherprocessing device. Other devices (not shown) are also located onexternal network 26. For example, external network 26 may containrouters, switches, and the like (not shown), which receive data packetsand which forward the data packets along paths to their intendeddestinations. Other servers, personal computers, mainframes, andprocessing devices (not shown) may also be on, and/or have access to,external network 26.

Server 44 acts as an intermediary for communications between clientapplication 24 and server application 39 in the manner described below.Server 44 runs HTTP (Hypertext Transfer Protocol) and is “visible” toother devices, such as device 15, via external network 26.

In more detail, server 44 is used in passing data between clientapplication 24 and server application 39 because these applicationscannot address each other directly. That is, since both applications areon local networks, they do not have universally-recognized networkaddresses. As such, the client and server applications cannot addressone another without the aid of server 44.

Server 44 includes a controller, such as a microprocessor, for executingsoftware (machine-executable instructions) stored in a memory to performthe functions described below. To avoid confusion in terminology, thefollowing reads as though those functions are performed by server 44,even though software in server 44, namely virtual tunneling application45, performs the functions.

In this embodiment, server 44 contains a processor 46, a memory 47, anda storage medium 49 for storing, among other things, an operating system(OS) 50, software 51 for effecting network communication, and one ormore applications. Processor 46 may execute software, including theapplications, out of memory 47. Among these applications is tunnelingapplication 45.

Tunneling application 45 creates a virtual tunnel between clientapplication 24 on client local network 14 and server application 39 onserver local network 30. Tunneling application 45 includes process 54(FIG. 3) to establish the virtual tunnel, as described below. Thevirtual tunnel allows client application 24 and server application 39 tocommunicate even though they are both behind firewalls and cannotdirectly address each other.

The virtual tunnel is also advantageous because it preserves theprotocols running on local networks 14 and 30. That is, data istransferred through the virtual tunnel via an intermediary protocol,such as HTTP, that is run on external network 26. The protocols runningon local networks 14 and 30 are essentially transmitted via the protocolof external network. When data reaches its destination, e.g., at localnetwork 14 or 30, the local protocol is thus recovered by either proxy29 or agent 42, thereby enabling the same protocol to be used at boththe source and destination local networks. Proxy 29 and agent 42 areboth capable of converting between a local protocol and the intermediaryprotocol. In this regard, it is noted that the intermediary protocol maybe the same as, or different from, the local protocols.

FIG. 3 shows process 54 that is performed by proxy 29, server 44, andagent 42 to set-up a virtual tunnel for a communication session betweenclient application 24 and server application 39. The section of FIG. 3labeled “Agent” corresponds to functions performed by agent 42; thesection of FIG. 3 labeled “Proxy” corresponds to functions performed byproxy 29; and the section of FIG. 3 labeled “Server” corresponds tofunctions performed by tunneling application 45 (on server 44).

Referring to FIG. 3, agent 42 sends (60), to server 44, interfaceinformation, including, but not limited to, interface names and portnumbers of agent 42 associated with server application 39. The interfaceinformation may be sent, e.g., in response to installing agent 42 onlocal network 30. Server 44 receives (61) the interface information andstores the interface information in a database (not shown). The databaseis associated with agent 42.

Information in the database may be made accessible to a user, e.g., atdevice 15 via a Web browser. The information may be made accessible viaa Web page (not shown) provided by server 44. The Web page may contain alist of devices on local network 30 that may be accessed via virtualtunneling. The identities of the devices, which may be provided toserver 44 along with the interface information, are associated withsoftware interfaces to such devices. When a user selects a device toconnect to, the user is, in effect, selecting an interface of agent 42.

A user who wants to connect to a device on local network from clientapplication 24 logs into server 44 via a Web page (not shown). The userthen selects a device (and, thus, an interface) to begin a communicationsession with that device. Server 44 receives (62) the input from the Webpage. As noted above, the Web page may contain an applet that comprisesproxy 29. In this case, when the user selects a device and enters theselection, the applet may be installed on device 15 as proxy 29.

Server 44 may control access to agents and interfaces through apredefined security (access) policy. For example, server 44 may allowsome users, but not others, access to devices on local network 30.Likewise, users may be restricted as to which devices they may access.Server 44 may control access based on user IDs (identifiers) and/orpasswords assigned to system users. For example, server 44 may maintaina database of user IDs and/or passwords corresponding to devices thatare accessible via those user IDs and/or passwords. If a user attemptsto establish a communication session with a device for which he has notbeen permitted access, server 44 may provide that user with an errormessage or the like.

Assuming that the user has access to the requested device, in process54, server 44 creates (63) a session object for the currentcommunication session. The session object contains message queues. Themessage queues are used to store data that is passed between clientapplication 24 and server application 39.

In this embodiment, the session object contains two message queues(other embodiments may contain more, or less, message queues). Onemessage queue is for data going from client application 24 to serverapplication 39 and the other message queue is for data going from serverapplication 39 to client application 24.

The session object also has an associated session identifier, referredto as a “sessionID” string. The sessionID string may be a uniquealphanumeric identifier that identifies communications associated with aparticular communication session. As described below, all data transfersassociated with a communication session between client application 24and server application 39 pass through server 44. The sessionID stringis used by server 44 (in particular, by tunneling application 45) tostore the data in the appropriate message queues(s).

In process 54, server 44 sends (64) the sessionID string and selectedinterface name to agent 42. Agent 42 receives (65) this message andcreates (66) a socket using the port and IP address that correspond tothe selected interface name. Agent 42 connects (67) the socket to serverapplication 39. If connection fails, agent 42 reports an error to server44. It is noted that sockets are used in this embodiment because theyare a well-known way of communicating. Other means of communication maybe used, including proxies, pipes, serial communications, etc.

In process 54, server 44 also sends (64) the sessionID string and portor other protocol parameters to proxy 29. Proxy 29 receives (68) thismessage and creates (69) a socket using the port that corresponds toclient application 24. Proxy 29 then provides (70) an “accept”instruction on that socket. The accept instruction enables proxy 29 toaccept data from client application 24.

Both proxy 29 and agent 42 execute a software thread to poll (71, 72)for data on their respective sockets, and also to poll for data fromserver 44. When data from client application 24 is received on a socketof proxy 29, proxy 29 appends the appropriate sessionID string to thedata and passes the data to server 44. The sessionID string enablesserver 44 to identify the data as belonging to a particularcommunication session, and to store the data in the appropriate messagequeue. Agent 42 polls for data from server 44, meaning that it searchesfor data from server 44 that is stored in message queues for agent 42.If there is data present, agent 42 retrieves the data, identifies thecommunication session using the sessionID string associated with thedata, and passes the data to server application 39 via the establishedsocket.

The converse occurs for data passed from server application 39 to clientapplication 24. More specifically, data from server application 24 isreceived on a socket of agent 42. Agent 42 appends the sessionID stringfor the current communication session to the data and passes the data toserver 44. Proxy 29 polls for data from server 44. If there is datapresent in an appropriate message queue, proxy 29 retrieves the data,identifies the communication session using the sessionID string, andpasses the data to client application 24.

On each socket, a select or “recv” (receive) instruction (command)determines if there is data to read. When data is read from a socket,the data may be sent to server 44 (by proxy 29 or agent 42) as the bodyof an HTTP POST command. Data in server 44 may be polled (by proxy 29 oragent 42) using an HTTP GET command. If there is data in server 44, thedata is passed in a reply to the GET command. This data is then writtento the appropriate socket. When an HTTP command is sent, its URLparameters include a “session=SSS” parameter, where “SSS” is thesessionID for a communication session.

As noted above, server 44 has a session object that contains two messagequeues. Data sent from proxy 29 is stored in one message queue anddelivered when agent 42 issues a GET command. The other message queuecontains data being passed from agent 42 to proxy 29.

Proxy 29 and agent 42 may encrypt communications sent to server 44.Examples of encryption that may be used include Secure Sockets Layer(SSL) and Hyper Text Transfer Protocol Secure sockets (HTTPS). Therecipient (e.g., proxy 29 or agent 42) should have sufficientcapabilities to perform any necessary decryption.

In this embodiment, there are two ways to end a communication session(i.e., terminate a virtual tunnel). The session may end when eitherclient application 24 or server application 39 closes its socket.However, some applications open and close sockets during the normalcourse of communications. For applications such as these, the user mayterminate the session manually when the applications are finishedrunning. The user may choose a termination scenario when creating thesession.

Server 44 may maintain an audit log (i.e., record) of communicationsessions. The audit log may identify the user, time, duration, agent,interface, and number of bytes transferred in a communication session.The actual data may be stored as human-readable text or in anotherformat. Audit logs are particularly advantageous in diagnostic andrepair scenarios, where it is often necessary to identify devicemodifications and repairs after the fact.

Server 44 may be associated with multiple servers, one or more of whichmay act as a load balancing server to distribute communications amongstother servers. In this case, when a session object is created, thesession object may be created on a server that has the most (or greaterthan a predetermined amount of) resources available and/or a server thatis located closest to (or within a predetermined location of) agent 42.In this case, the Uniform Resource Locator (URL) of the server that isbeing used to effect communication is sent to agent 42 and proxy 29,along with the sessionID. In all subsequent communications, proxy 29 andagent 42 include the URL of the server. This ensures that a singleserver handles a single communication session.

The virtual tunnel system described herein is not limited to use withthe hardware/software configuration of FIGS. 2 and 3; it may findapplicability in any computing or processing environment. Thefunctionality of the virtual tunnel system, including, but not limitedto, the functions performed by proxy 29, server 44, and agent 42, may beimplemented in hardware (e.g., an ASIC {Application-Specific IntegratedCircuit} and/or an FPGA {Field Programmable Gate Array}), software, or acombination of hardware and software.

The virtual tunnel system may find applicability in any computing orprocessing environment and with any type of machine that is capable ofrunning machine-readable instructions, such as one or more computerprograms.

The virtual tunnel system can be implemented in digital electroniccircuitry, or in computer hardware, firmware, software, or incombinations of them. The virtual tunnel system can be implemented as acomputer program product, i.e., a computer program tangibly embodied inan information carrier, e.g., in a machine-readable medium or in apropagated signal, for execution by, or to control the operation of,data processing apparatus, e.g., a programmable processor, a computer,or multiple computers. A computer program can be written in any form ofprogramming language, including compiled or interpreted languages, andit can be deployed in any form, including as a stand-alone program or asa module, component, subroutine, or other unit suitable for use in acomputing environment. A computer program can be deployed to be executedon one computer or on multiple computers at one site or distributedacross multiple sites and interconnected by a communication network.

Method steps implemented to effect virtual tunneling can be performed byone or more programmable processors executing one or more computerprograms to perform functions described herein by operating on inputdata and generating output. Method steps can also be performed by, andthe virtual tunnel system can be implemented as, special purpose logiccircuitry.

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. Elements of a computer include aprocessor for executing instructions and one or more memory devices forstoring instructions and data. Generally, a computer will also include,or be operatively coupled to receive data from, or transfer data to, orboth, one or more mass storage devices for storing data, e.g., magnetic,magneto-optical disks, or optical disks. Information carriers suitablefor embodying computer program instructions and data include all formsof non-volatile memory, including by way of example semiconductor memorydevices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks,e.g., internal hard disks or removable disks; magneto-optical disks; andCD-ROM and DVD-ROM disks. The processor and the memory can besupplemented by, or incorporated in special purpose logic circuitry.

The virtual tunnel system can be implemented in a computing system thatincludes a back-end component, e.g., as a data server, or that includesa middleware component, e.g., an application server, or that includes afront-end component, e.g., a client computer having a graphical userinterface or a Web browser through which a user can interact with thevirtual tunneling system, or any combination of such back-end,middleware, or front-end components. The components of the system can beinterconnected by any form or medium of digital data communication,e.g., a communication network. Examples of communication networksinclude a local area network (“LAN”) and a wide area network (WAN”),e.g., the Internet.

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

The process described above is not limited to the implementations setforth herein. For example, the process is not limited to use with thevirtual tunnel system described herein, but rather may be implemented inany type of network-based communication system.

It is noted that client application 24 and server application 39 maycommunicate directly when a direct connection can be achieved (e.g., ifthey are on the same network). To effect direct communication, if clientapplication 24 and server application 39 use TCP/IP, server application39 creates a socket on a specific port. Client application 24 alsocreates a socket and connects to this port. If server application 39runs on another computer, client application 24 also specifies thenetwork address of that computer. At this point, the client and serverare connected and begin communicating.

The local protocols run on local networks 14, 30 may be TCP/IP or aserial protocol, such as RS232 or RS485. The protocol run on externalnetwork 26 may be HTTP. The virtual tunnel may comprise a telnet session(e.g., the tunnel is implemented during the telnet session).

It is noted that more than one agent may be present on local network 30and more than one proxy may be present on local network 14. There may bea one-to-one correspondence between devices and agents and betweendevices and proxies. Alternatively, a single proxy may service differentdevices and, likewise, a single agent may service different devices.Similarly, multiple proxies may service the same device and multipleagents may service the same device.

The sessionID string may expire after a predetermined period of time,necessitating a new communication session. For example, the sessionIDmay expire after a period during which no communications are exchanged.This period may be programmed into server 44. Similarly, the sessionIDstring expires when a communication session terminates.

Other embodiments not described herein are also within the scope of thefollowing claims.

1. A method, performed by at least one device, for transferring data viaa communication session between a client application and a serverapplication, the method comprising: assigning an identifier to thecommunication session; creating at least one queue associated with thecommunication session; storing data passed between the clientapplication and the server application in the at least one queue, thedata being stored using the identifier; and receiving, from the clientapplication, a command to obtain data in the at least one queue that isdestined for the client application and that is present at a time thecommand from the client application is received, and receiving, from theserver application, a command to obtain data in the at least one queuethat is destined for the server application and that is present at atime the command from the server application is received, the commandreceived from the client application being a hypertext transfer protocol(HTTP) command to retrieve data from the at least one device, and thecommand received from the server application being an HTTP command toretrieve data from the at least one device; wherein the clientapplication and the server application run local protocols, and the datais passed between the client application and the server application viaan intermediary protocol; and wherein the client application is behind afirst firewall, the server application is behind a second firewall, andthe at least one device is not behind either the first firewall or thesecond firewall.
 2. The method of claim 1, wherein the clientapplication and the server application are on networks that run thelocal protocols, and wherein conversion between the local protocols andthe intermediary protocol occurs prior to passing the data through thedevice.
 3. The method of claim 2, wherein the local protocols compriseat least one of TCP/IP and a serial protocol, the serial protocolcomprising one of RS232 and RS485.
 4. The method of claim 1, furthercomprising: creating a socket interface to at least one of the clientapplication and the server application, data from the at least onedevice being transmitted through the socket interface.
 5. The method ofclaim 1, wherein the identifier is associated with the at least onequeue.
 6. The method of claim 1, wherein the at least one devicecomprises a server, and the method further comprises: performing loadbalancing to select the server to perform the method from among pluralservers.
 7. The method of claim 1, wherein the identifier is invalidatedwhen the communication session terminates.
 8. The method of claim 1,wherein the communication session comprises a telnet session.
 9. Themethod of claim 1, wherein the communication session is effected via aWeb site.
 10. The method of claim 1, further comprising maintaining asession record, the session record including an identity associated withinitiation of the session.
 11. The method of claim 1, wherein theintermediary protocol is different from the local protocols.
 12. Themethod of claim 1, wherein the intermediary protocol is a same protocolas the local protocols.
 13. A machine-readable medium storesinstructions for use in transferring data via a communication sessionbetween a client application and a server application the instructionsbeing executable by at least one machine, the instructions for causingthe at least one machine to: assign an identifier to the communicationsession; create at least one queue associated with the communicationsession; store data passed between the client application and the serverapplication in the at least one queue, the data being stored using theidentifier; and receive, from the client application, a command toobtain data in the at least one queue that is destined for the clientapplication and that is present at a time the command from the serverapplication is received, and receive, from the server application, acommand to obtain data in the at least one queue that is destined forthe server application and that is present at a time the command fromthe server application is received, the command received from the clientapplication being a hypertext transfer protocol (HTTP) command toretrieve data from the at least one machine, and the command receivedfrom the server application being an HTTP command to retrieve data fromthe at least one machine; wherein the client application and the serverapplication run local protocols, and the data is passed between theclient application and the server application via an intermediaryprotocol; and wherein the client application is behind a first firewall,the server application is behind a second firewall, and the at least onemachine is not behind either the first firewall or the second firewall.14. The machine-readable medium of claim 13, wherein the clientapplication and the server application are on networks that run thelocal protocols, and wherein conversion between the local protocols andthe intermediary protocol occurs prior to passing the data through theat least one machine.
 15. The machine-readable medium of claim 14,wherein the local protocols comprise at least one of TCP/IP and a serialprotocol, the serial protocol comprising one of RS232 and RS485.
 16. Themachine-readable medium of claim 13, wherein the intermediary protocolis different from the local protocols.
 17. The machine-readable mediumof claim 13, wherein the intermediary protocol is a same protocol as thelocal protocols.
 18. The machine-readable medium of claim 13, furthercomprising instructions to: create a socket interface to at least one ofthe client application and the server application, data from the atleast one machine being transmitted through the socket interface. 19.The machine-readable medium of claim 13, wherein the identifier isassociated with the at least one queue.
 20. The machine-readable mediumof claim 13, wherein the at least one machine comprises a server, andthe machine-readable medium further comprises instructions to: performload balancing to select the server.
 21. A system for transferring datavia a communication session between a client application and a serverapplication, the client application running on a first network and theserver application running on a second network, the system comprising: aproxy having a socket to the client application, the proxy to convertdata between a local protocol run on the first network to a non-localprotocol; an agent having a socket to the server application, the agentto convert data between a local protocol run on the second network andthe non-local protocol; and a server to enable communication between theproxy and the agent, the server containing a message queue dedicated tothe communication session, the message queue for storing datatransmitted during the communication session, wherein the server isconfigured to receive, from the client application, data in the messagequeue destined for the server application, and to receive, from theserver application, data in the message queue destined for the clientapplication; wherein the server is configured to receive, from theclient application, a command to obtain data in the message queue thatis destined for the client application and that is present at a time thecommand from the client application is received, and to receive, fromthe server application, a command to obtain data in the message queuethat is destined for the server application and that is present at atime the command from the server application is received, the commandreceived from the client application being a hypertext transfer protocol(HTTP) command to retrieve data from the server, and the commandreceived from the server application being an HTTP command to retrievedata from the server; and wherein the client application and the firstnetwork are behind a first firewall, the server application and thesecond network are behind a second firewall, and the server is notbehind either the first firewall or the second firewall.
 22. The systemof claim 21, wherein, the proxy obtains the data from the message queueand passes the data to the client application.
 23. The system of claim21, wherein, the agent obtains the data from the message queue andpasses the data to the server application.